This invention relates to the catalytic cure of dialkenylbenzene monomers. In a specific aspect, the invention relates to the preparation of low dielectric constant thermosets for electrical laminating applications.
For electrical lamination, in which a glass substrate is impregnated with a thermosettable resin for ultimate use as a printed circuit board, low dielectric constant thermoset materials are desirable. Pure hydrocarbon materials give promise for achieving the desired low dielectric constant, since polar groups tend to raise the dielectric constant of the polymer. Liquid butadiene oligomers cured with peroxides have been used as an all-hydrocarbon laminating material, but cure is slow and large quantities of peroxides are required. Divinylbenzene and divinylbenzene/styrene mixtures cured with free radical initiators provide another all-hydrocarbon system, but these monomers are undesirably volatile and tend to gel at a low conversion level, leading to shrinkage and cracking in the cured material.
It is therefore an object of the invention to provide a curable composition which cures to a low dielectric constant thermoset material. In one embodiment, it is an object of the invention to provide a process for preparing a low dielectric constant thermoset material which addresses the problem of premature gelation of the uncured system.